The San Antonio Center for Research in Reproductive Biology will be a multidisciplinary research effort, oriented to the development of new alternative methods of contraception. We propose to investigate reproductive mechanisms at several levels, including: neuroendocrine control of ovulation; hormone-receptor-chromatin interactions in breast, oviduct, and uterus; regulation of tubal transport. Our definitive objective is utilization of the information acquired to design innovative methods of contraception. Six senior scientists will form the Research Program Committee of the Center. Each will supervise the activities of less established investigators within his area of special competence. A Research Advisory Committee of outside experts has been formed, and each year they will review the scientific program of the Center. Thirty-nine scientists will be involved in the Center at its inception. Although the proposed Center will emphasize Biomedical Research, we have an active and close interaction with behavioral and social scientists from the Population Research Center at The University of Texas at Austin, and from the Division of Sociology of the Health Science Center. These behavioral scientists teach in our postdoctoral training program in Reproductive Biology and Voluntary Regulation of Fertility. The applicant institution has demonstrated, by past and present actions, a strong commitment to research and training in population-related fields.